inspect-js
This github and npm organization houses JavaScript projects that help you look at stuff.
Predicates
Functions that ask a question and produce a yes or no answer (`true` or `false`).
- is-arguments -
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- Is this an arguments object? It's a harder question than you think. - is-arrow-function -
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- Determine if a function is an ES6 arrow function or not. - is-bigint -
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- Is this value an ES BigInt? - is-boolean-object -
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- Is this value a JS Boolean? This module works cross-realm/iframe, and despite ES6 @@toStringTag. - is-boxed-primitive -
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- Is this value a boxed primitive? Shim for node's util.isBoxedPrimitive. - is-callable -
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- Is this JS value callable? Works with Functions and GeneratorFunctions, despite ES6 @@toStringTag. - is-core-module -
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- Is this specifier a node.js core module? - is-date-object -
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- Is this value a JS Date object? This module works cross-realm/iframe, and despite ES6 @@toStringTag. - is-finalizationregistry -
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- Is this value a JS FinalizationRegistry? This module works cross-realm/iframe, and despite ES6 @@toStringTag. - is-generator-function -
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- Determine if a function is a native generator function. - is-map -
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- Is this value a JS Map? This module works cross-realm/iframe, and despite ES6 @@toStringTag. - is-negative-zero -
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- Is this value negative zero? === will lie to you - is-number-object -
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- Is this value a JS Number object? This module works cross-realm/iframe, and despite ES6 @@toStringTag. - is-object -
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- Checks whether a value is an object - is-regex -
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- Is this value a JS regex? Works cross-realm/iframe, and despite ES6 @@toStringTag - is-set -
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- Is this value a JS Set? This module works cross-realm/iframe, and despite ES6 @@toStringTag. - is-shared-array-buffer -
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- Is this value a JS SharedArrayBuffer? - is-string -
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- Is this value a JS String object or primitive? This module works cross-realm/iframe, and despite ES6 @@toStringTag. - is-symbol -
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- Determine if a value is an ES6 Symbol or not. - is-typed-array -
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- Is this value a JS Typed Array? This module works cross-realm/iframe, does not depend on instanceofor mutable properties, and despite ES6 Symbol.toStringTag. - is-weakmap -
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- Is this value a JS WeakMap? This module works cross-realm/iframe, and despite ES6 @@toStringTag. - is-weakref -
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- Is this value a JS WeakRef? This module works cross-realm/iframe, and despite ES6 @@toStringTag. - is-weakset -
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- Is this value a JS WeakSet? This module works cross-realm/iframe, and despite ES6 @@toStringTag.
Comparisons
Packages that compare two things.
Environment
Packages that tell you about the JS env.
- available-typed-arrays -
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- Returns an array of Typed Array names that are available in the current environment - functions-have-names -
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- Does this JS environment support the nameproperty on functions? - has-bigints -
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- Determine if the JS environment has BigInt support. - has-dynamic-import -
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- Does the current environment have import()support? - has-object-spread -
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- check if the environment supports { ...a } spread syntax - has-package-exports -
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- Does the current node version have support for the "exports" field in package.json? - has-package-imports -
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- Does the current node version have support for the "imports" field in package.json? - has-package-self-reference -
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- Does the current node version have support for requiring/importing its own name? - has-private-fields -
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- Determine if the JS environment has private fields (class { #x; }) support. - has-strict-mode -
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- Does the current JS environment have strict mode? ES5+ should; but let's not assume. - has-symbols -
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- Determine if the JS environment has Symbol support. Supports spec, or shams. - has-template-literals -
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- Determine if the JS environment has template literal support. - has-tostringtag -
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- Determine if the JS environment has Symbol.toStringTagsupport. Supports spec, or shams. - has-typed-arrays -
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- Does this environment have JS Typed Arrays?
Describe
Packages that tell you about a specific JS value.
- get-symbol-description -
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- Gets the description of a Symbol. Handles Symbol()vsSymbol('')properly when possible. - object-inspect -
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- string representations of objects in node and the browser - typed-array-length -
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- Robustly get the length of a Typed Array - which-boxed-primitive -
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- Which kind of boxed JS primitive is this? - which-builtin-type -
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- What is the type of this builtin JS value? - which-collection -
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- Which kind of Collection (Map, Set, WeakMap, WeakSet) is this JavaScript value? Works cross-realm, without instanceof, and despite Symbol.toStringTag. - which-typed-array -
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- Which kind of Typed Array is this JavaScript value? Works cross-realm, without instanceof, and despite Symbol.toStringTag.

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